Chain of Custody Instructional Video

Analytical testing dots


How to Fill Out a Chain of Custody

In the environmental industry, following proper procedures to fill out the Chain of Custody serves two main goals:  (1) to ensure that the sample which is taken or collected, is the same sample which is analyzed or tested; and (2) to ensure that the sample is not altered, changed, substituted, or tampered with between the field collection and submission to the lab for testing.

Every sample that is sent to a laboratory should be accompanied by a Chain of Custody which is normally provided in the sampling kit sent to you by the laboratory.

The COC also is the written contract detailing which analyses should be run on the samples.

1. The client contact area contains contact information as well as the sampler’s signature.  It is very important that that everything written on a COC be legible and accurate. Most are filled out with permanent ink.

2. The sample information area contains sample IDs that will allow the sample to tie a sample back to a specific location at the site. These sample IDs are the identifiers that will end up on the report pages.

3. Samplers need to be very careful to write these sample ID legibly. Make sure your number one can be recognized as a 1 and not an I, zero, and can be differentiated from the letter O, S can be differentiated from the number 5. It’s a good idea to verify your sample IDs and the number of bottles you place in your shipping container. A common problem is the number or type of samples in the shipping container does not match the number or type of samplers noted on the Chain of Custody;

4. The request for analysis area – this is where you tell the lab which tests should be run on which samples. This is the legal contract with the lab the absence of any other instructions. Please use the actual method numbers. It’s not enough to just note a program reference like NOAA or PSSDA as there are several methods covered under each program. If you’re unsure what the method numbers are, contact your project chemist.

5. Most Chain of Custodies provide a comment area where you can indicate any special preparation needed or any additional information to the laboratory.

6. Use the deliverables section to indicate the report requirements, level of QC needed, level of information provided in the report, turnaround requirements, or invoice information including billing and contact information.

7. Finally, the area stating who collected the sample and  who received it upon its arrival must be signed by both parties. Most laboratories also have an internal Chain of Custody indicating the sample’s whereabouts within the lab once analysis has begun.

A properly filled out Chain of Custody is the key to a well run project.


Click here to view & download Chain of Custody forms...